Intercell interference occurs when signals transmitted in neighboring cells interfere with signals transmitted in a particular cell. Handling intercell interference at a cell border area may be beneficial for existing as well as future communication systems in order to guarantee efficient use of available bandwidth. Intercell interference coordination (ICIC) aims at reducing the level of interference and/or mitigating the impact of interference generated by cells that neighbor a particular cell while maintaining quality in the particular cell. Some ICIC techniques include power control, fractional loading, frequency reuse, and dynamic channel allocation. For example, in Global System for Mobile communications (GSM), some systems operate a broadcast channel (BCH) carrier in a certain frequency band with a frequency reuse larger than a frequency reuse provided for other carriers (e.g., a reuse factor of “12” compared to a reuse factor of “3”).
Many ICIC solutions result in resource allocations with improved and stabilized channel quality (e.g., signal-to-interference ratio) at the expense of more narrow allocations (e.g., smaller bandwidth). Whether the combined effect of these ICIC solutions is beneficial depends on characteristics of the services to be carried by the network.
An example of a service with limited bandwidth usage is Radio Resource Control (RRC). The RRC protocol is used in the control plane of the Third Generation (3G) and Beyond 3G (B3G) wireless stacks. RRC belongs to the Universal Mobile Telecommunications System (UMTS) Wideband Code Division Multiple Access (WCDMA) protocol stack and to the 3GPP Long Term Evolution (LTE) protocol stack, and handles control plane signaling of Layer 3 between user equipment (UE) and a UMTS Terrestrial Radio Access Network (UTRAN) and the Evolved UTRAN (E-UTRAN). RRC performs functions for connection establishment and release, broadcast of system information, Radio Bearer establishment/reconfiguration and releases, RRC Connection mobility procedures, paging notification and release, outer loop power control, etc. RRC messages are of limited size, but have stringent delay requirements. For the Long Term Evolution (LTE) project (a project within the Third Generation Partnership Project (3GPP) to improve the UMTS mobile phone standard), RRC messages are transmitted using downlink and uplink traffic channels (TCH), and are also interfered with by TCHs from other cells.
To improve robustness of RRC messages, some systems prioritize RRC messages in schedulers in order to reduce the queuing delay associated with RRC messages. Other systems apply an extra robust modulation and coding for RRC messages. This may reduce a number of retransmissions for RRC messages, and delay associated with RRC messages. However, none of these systems control interference associated specifically with RRC messages. The GSM system controls interference associated with the BCH carrier (not RRC messages), and at the expense of a separate frequency band for the BCH carrier.
Furthermore, it is not trivial to determine, at an ICIC level, how and/or which channels or resources carry a RRC message. Additionally, the RRC message may require a better ICIC level than the ICIC level required for user data.